Many methods of planning and guiding the proper position of dental implants have been revealed. Frequently a radiographic template is made to fit to the patient's teeth, and radiographic markers are attached to the template. Klein (U.S. Pat. No. 5,967,777) revealed a method that uses a plastic replica of the prospective teeth to be supported by dental implants. This is a time consuming process since a dental laboratory technician must set or carve teeth to fit in the ideal position for a given patient. The patient is then scanned with the radiographic template, preferably using computed tomography (CT). If the patient has teeth that will be removed at the time of implant placement, it is difficult to image these areas since the teeth are still present and radiographic scatter frequently makes it difficult to determine the actual shape of the teeth. It is also difficult to position the template in a predictable position after the teeth to be removed. Other methods have been revealed that require the patient's teeth be removed first and removable dentures made.
The NobelGuide™ (Nobel Biocare) system uses this technique. After healing, radiographic markers are placed in the dentures and the patient is imaged using CT. A second scan of the patient's denture is made of the denture alone, and then the radiographic markers are used to align the two CT scans in the same computer space. The Nobel system allows for planning of the dental implant position in relation to the patient's denture and the supporting bone, but it requires that the patient's dentures be damaged by placing gutta percha markers in the plastic to align the images. If the dentures are not used, then they are duplicated to make a new set with radiographic markers. Generally, the duplicate set is less accurate, which involves an additional cost and source of errors.
Thus, there is a need for an improved method of imaging a patient and planning for implant placement that provides for the virtual positioning of artificial teeth in harmony with the patient's facial structure and appearance and the virtual positioning of implants in relation to the remaining bone. There is also a need for a method of communicating this information easily to the surgeon, restorative dentist and laboratory. It is also desirable that changes can be made in the virtual plan such that the surgeon, restorative dentist or laboratory can modify the treatment plan as needed.